Agglutination reaction slide

Abstract

A test element for agglutination tests, comprising a receiving and mixing region for a sample and reagents and a reaction capillary having an upstream region which produces a capillary effect causing the sample-reagents mixture to flow at a speed which is greater than along a downstream region of the reaction capillary. An intermediate region can be provided between the upstream capillary region and the downstream region. The downstream end of capillary is connected to a collecting region. The test element is characterized by continuous supply and movement of the sample-reagents mixture through the reaction capillary. More particularly the time needed for a sample-reagents mixture to flow from the upstream end to the downstream end of the reaction capillary fluctuates only slightly between tests. The test element is particularly suitable for detecting drugs of abuse such as cocaine metabolites in human body fluids.

I claim: 
     
       1. A test element for an agglutination test of a sample-reagent mixture, comprising at least one pair of plate members defining therebetween a reaction capillary having a predetermined thickness for the sample-reagent mixture to flow through the capillary, the reaction capillary having an input end and an output end, the input end of the reaction capillary being fluidically connected to a zone for receiving and mixing the sample with the reagent, wherein: the reaction capillary has a substantially rectangular cross-sectional configuration in a direction perpendicular to the flow of the sample-reagent mixture,   the reaction capillary further has an upstream region with a thickness at the input end of between about 50 and about 100 μm and a downstream region with a thickness at the output end of between about 200 and about 300 μm, the thickness of the reaction capillary increasing from the upstream region toward the downstream region, and   the increase in the reaction capillary thickness is substantially continuous and linear over the length of each region.   
     
     
       2. The test element of claim 1, wherein the smallest reaction capillary thickness in the downstream region is at least as large as the largest reaction capillary thickness in the upstream region. 
     
     
       3. The test element of claim 1, wherein the reaction capillary has an intermediate region disposed between the upstream region and the downstream region and fluidically communicating with said upstream and downstream regions, the intermediate region being of such dimensions so as to provide a capillary effect which causes the sample-reagent mixture to flow at a speed which is equal to or less than the speed along the upstream region. 
     
     
       4. The test element of claim 1, wherein the reaction capillary has an intermediate region disposed between the upstream region and the downstream region and fluidically communicating with said upstream and downstream regions, the intermediate region being of such dimensions so as to provide a capillary effect which causes the sample-reagent mixture to flow at a speed which is equal to or greater than the speed along the downstream region. 
     
     
       5. The test element of claim 1, wherein the reaction capillary has an intermediate region disposed between the upstream region and the downstream region and fluidically communicating with said upstream and downstream regions, the intermediate region being of such dimensions so as to provide a capillary effect which causes the sample-reagent mixture to flow at a speed which is equal to or less than the speed along the upstream region and equal to or greater than the speed along the downstream region. 
     
     
       6. The test element of claim 5, wherein the reaction capillary has a substantially S-shaped configuration along the direction of flow of the sample-reagent mixture. 
     
     
       7. The test element of claim 1, wherein each plate member of said at least on pair of plate members has a predetermined length, and the reaction capillary has a length which is greater than the length of one of said plate members. 
     
     
       8. The test element of claim 7, wherein the reaction capillary has a substantially S-shaped configuration along the direction of flow of the sample-reagent mixture. 
     
     
       9. The test element of claim 7, further comprising a collection region fluidically connected to the output end of the reaction capillary. 
     
     
       10. The test element of claim 9, wherein at least one of the plate members is made from transparent plastics. 
     
     
       11. A test element for use in detecting the agglutination of a sample-reagent mixture, comprising a top plate member and a bottom plate member secured together, at least one of said plate members defining a channel having a predetermined thickness and configured to form a reaction capillary between the plate members for passing the sample-reagent mixture therethrough, the reaction capillary having an input end and an output end, the reaction capillary having an upstream region with a thickness at the input end of between about 50 and about 100 μm and with means defining an aperture at the input end for receiving the sample-reagent mixture, and a downstream region fluidically communicating with the upstream region and with a thickness at the output end of between about 200 and about 300 μm, wherein the reaction capillary has a substantially rectangular cross-sectional configuration in a direction perpendicular to the flow of the sample-reagent mixture, the thickness of the reaction capillary increases in a direction from the upstream region toward the downstream region, and the increase of the reaction capillary thickness is substantially continuous and linear over the length of each region. 
     
     
       12. The test element of claim 11, wherein the top plate member has means defining an aperture forming thereunder with the bottom member a chamber for receiving and mixing the sample and at least one reagent to form the sample-reagent mixture, the chamber fluidically communicating with the aperture in the upstream region of the reaction capillary. 
     
     
       13. The test element of claim 12, wherein the upstream and downstream regions have substantially equal lengths. 
     
     
       14. The test element of claim 12, wherein the capillary further comprises an intermediate region having ends which fluidically communicate with the upstream region and downstream region, respectively. 
     
     
       15. The test element of claim 12, further comprising a collecting chamber fluidically connected to the output end of the reaction capillary. 
     
     
       16. The test element of claim 12, wherein the top and bottom plate members each have predetermined lengths and the reaction capillary has a length which is greater than the length of at least one of said top and bottom plate members. 
     
     
       17. The test element of claim 16 wherein the reaction capillary has a substantially S-shaped configuration along the direction of flow of the sample-reagent mixture.